1. Field of the Invention
The present invention relates to a laser corneal surgery apparatus for ablating a cornea of a patient's eye by a laser beam for the purpose of correcting a refractive error and the like.
2. Description of Related Art
As keratorefractive surgery using an excimer laser beam which is ultraviolet light, laser assisted in-situ keratomileusis (LASIK) is performed, in which a flap is formed by incising the part from an epithelium to a stroma in layered form, the stroma is ablated (removed) by irradiating a laser beam, then the flap is returned.
A corneal incision apparatus called a microkeratome is used for forming a flap. As disclosed in European Patent Application Publication No. 956840 A2 corresponding to Japanese Patent Application Unexamined Publication No. HEI 11-342151, such an apparatus has been known that a corneal pressing member presses the corneal part projecting from an opening of a suction part sucking and being fixed on a corneal surface so that the projecting part is flattened, then a blade is transversely oscillated and moved straight or rotatably moved to incise the epithelium.
When a surgical operator uses the corneal incision apparatus described above, he may confirm operations of a blade drive using a microscope included in the laser corneal ablation apparatus. In this case, since water (physiological saline) is used as a lubricant to the blade, a spray of water forms, whereby water droplets may adhere to an optical member (a mirror or lens) placed nearest to the cornea to be irradiated in the optical system for guiding and irradiating the excimer laser beam onto the cornea. In general, a coating of a mirror reflecting ultraviolet light is water-sensitive, and adhesion of the water droplets affects the laser irradiation. Further, since water is used for preventing the cornea from getting dry during corneal incision, water droplets generated incident to the blade drive of the corneal incision apparatus may adhere to the optical member nearest to the cornea.